Abstract: A plurality of dielectric sheets are laminated and bonded together to constitute a laminated board. A plurality of strip-shaped resonance electrodes are formed in parallel on a predetermined bonding face of the dielectric sheets, and the strip-shaped resonance electrodes reach opposite edges of the laminated board. Recesses are formed by locally cutting out the portions of the edges of the laminated board in which the respective resonance electrodes are exposed at their particular ends. Grounding electrodes are respectively formed on the obverse and reverse faces of the laminated board, and edge grounding electrodes are formed in the portions of the opposite edges of the laminated board except for the recess.

Abstract: A new method for preparation of Mn-Zn or Ni-Zn type ferrite single crystals. The ferrite materials are provided in a lower portion of a crucible and completely dissolved. The crucible is moved within a predetermined atmosphere of temperature gradient. A solid which is equilibrium in composition to the ferrite materials is supplied into the crucible while the dissolved ferrite materials are crystallizing from the lower extremity while a liquid-phase zone is maintained constant in depth. Ferrite single crystals of at least about 800 mm in length are grown which are homogeneous in composition throughout their length.

Abstract: A process for producing Ni-Mn-Zn ferrite single crystal for high frequency wherein a sample comprising 10-30 molar percent of NiO, 1.8-12 molar percent of MnO, 15-35 molar percent of ZnO and 49-53 molar percent of Fe.sub.2 O.sub.3 is melted and subjected to growing into a crystal under an oxygen partial pressure of below about 100 Kg/cm.sup.2.